The Internet Protocol (IP) Flow Mobility (IFOM) technology has been focused on a solution to transmitting and moving an IP flow between a number of access technologies for a User Equipment (UE) connected with the same Packet Data network (PDN) connection using the different access technologies. For example, an operator can require that a best effort IP flow shall be offloaded through a Wireless Local Area Network, and an IP flow for a specific Quality of Service (QoS) is required shall gain an access through an Evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRAN) for transmission.
The IFOM technology has been studied and standardized in the 3rd Generation Partnership (3GPP) System Architecture Working Group 2 (SA2) starting with the Release 10 (R10), where the IFOM technology has been standardized based upon a terminal mobility management protocol, a preliminary study has been made on the IFOM technology based upon a network mobility management protocol starting with the R11 (not yet in the R12).
I. The IFOM solution based upon a terminal mobility management protocol is as follows:
Such an IFOM solution based upon the Dual Stack Mobile IP version 6 (DSMIPv6) protocol (with an S2c interface) has been defined in the TS 23.261 that mobility of an IP flow is primarily based upon IP flow binding information as depicted in Table 1:
TABLE 1IP flow binding informationHomeRoutingAddressAddressBinding IDBID PriorityFlow IDFID PriorityRouting FilterHoA1CoA1BID1xFID1aDescription of IPflows . . .FID2bDescription of IPflows . . .HoA1CoA2BID2yFID3. . .. . .
Where the Home Address (HoA) is an IP address allocated by a Packet Data Network Gateway (PGW) for UE, the Care of Address (CoA) indicated by the Routing Address is an IP address of the UE at the non-3GPP side, the Binding ID (BID) is an identifier bound by the UE for an IP flow generated at each CoA, and provided with a priority, and the Flow ID (FID) defines a routing rule including a routing filter and a routing address, where the routing address is the HoA or the CoA.
If the UE is connected with the same PDN connection using a 3GPP access technology and a non-3GPP access technology, and decides to move an IP flow, then the UE will indicate information about the IP flow to be moved, to a PDN Gateway (PGW) in a Binding Update (BU) message, and particularly the UE indicates the updated routing rule to the PGW in the BU message; the PGW provides a Policy Control and Charging Rule Function (PCRF) entity with the received routing rule in an IP-Connectivity Access Network (CAN) Session Modify Request message; the PCRF entity stores mapping between a routing address and a Service Data Flow (SDF) which are received, and returns an IP-CAN Session Modify Response message to the PCRF entity; and the PGW indicates the routing rule accepted by the network to the UE in a Binding Acknowledge (BA) message.
II. The IFOM solution based upon a network mobility management protocol (NB-IFOM) is as follows:
Such IFOM solutions based upon the Proxy Mobile IP version 6 (PMIPv6) protocol (with S2a and S2b interfaces) and the General Packet Radio Service (GPRS) protocol (with an S2b interface) have been defined in the TR 23.861 that their general idea is the same as that of the DSMIPv6 based IFOM solution because the UE also indicates the updated routing rule to the PGW, except for their different applicable transmission protocols, so a repeated description thereof will be omitted here.
A UE-initiated NB-IFOM procedure has been defined, which may be triggered due to an Access Network Discovery and Selection Function (ANDSF) policy, a user preference, local operating environment information, etc. At present, a network initiated NB-IFOM also has been defined, which may be triggered due to network congestion, a change in IP flow characteristic, etc. However there has been absent so far particular solutions to initiating an NB-IFOM procedure by the network, and to defining an optimum IFOM strategy for both a UE-initiated NB-IFOM procedure and a network initiated NB-IFOM procedure.